Our prior application, Ser. No. 09/728,382, and the applications to which it is related, describe electrosurgical electrodes and handpieces for treating tissue in a surgical procedure commonly known as minimally invasive surgery (MIS). Among the features described and claimed in the prior application is an electrosurgical handpiece that can be used in MIS and reduces the danger of excessive heat causing possible patient harm. This is achieved in one embodiment by an electrosurgical handpiece that is bipolar in operation and that is configured for use in MIS. The bipolar operation confines the electrosurgical currents to a small active region between the active ends of the bipolar electrode and thus reduces the possibility that excessive heat will be developed that can damage patient tissue. Moreover, the position of the active region can be controlled to avoid patient tissue that may be more sensitive to excessive heat. In a preferred embodiment, the flexible end is achieved by weakening at the end the housing for the electrode, and providing a pull string or wire connected to the weakened housing end and with a mechanism at the opposite end for the surgeon to pull the string or wire to flex the housing end to the desired position. This feature allows the surgeon to position the active electrode end at the optimum location for treating, say, a herniated disk to remove undesired regions and to provide controlled heat to shrink the tissue during surgery. In one of the prior applications referred to in the referenced application, a suitable bipolar electrode is described, which comprises a pair of rounded electrodes with spaced flat sides separated by an insulating layer. The referenced application describes a bipolar probe comprising substantially hemispherically-shaped active electrode segments spaced apart by a thin insulator.
There is a need in the art for rigid electrodes, i.e., without a flexible end, for treating orthopedic ailments, such as for example joint ailments of the shoulder, knee and hip, especially in a minimally invasive surgery (MIS) environment, also referred to from time to time as arthroscopy.
The present invention is a continuation-in-part of the referenced prior application and hereby incorporates by reference the total contents of it and its four related prior applications, Ser. Nos. 09/303,839, 09/393,286, 09/425,313, and 09/483,994. The present invention describes and claims among other things a bipolar electrode comprising an active electrode at the distal end of a rigid non-flexible handpiece. Since the present application otherwise makes use of the same teachings of the prior applications, it was felt unnecessary to repeat in the body of this specification many of the details present in the contents of the prior application. The present description will be confined solely to the modifications in the handpiece or electrode which will still achieve the same benefits as with the constructions of the prior applications. For more details, the reader is directed to the prior applications.
The new handpiece end constructions of the present improvement uses the bipolar principle and are configured to provide more controlled distribution of the electrosurgical currents to the tissue to be modulated. By xe2x80x9cmodulationxe2x80x9d is meant ablation, cutting, smoothing, volumetric shrinkage, coagulation, hemostasis or cauterization.
In a preferred embodiment, the active electrode is formed by a projecting wire preferably extending laterally, or laterally and backwardly and connected to a first terminal of the bipolar source. The second terminal is connected to a return or ground electrode that is located rearward of the active electrode and is positioned on or inside of the handpiece but electrically accessible to electrosurgical currents emanating from the active electrode. The current path may include an electrically-conductive or semi-conductive fluid positioned between the active and return electrodes. The conductive fluid can be provided by an introduced fluid such as saline solution, or by body fluids normally present adjacent the tissue being modulated.
In a first preferred embodiment, the wire extends laterally, allowing its use as a cutting wire electrode and also as an ablative electrode. In a second preferred embodiment, the wire extends in a loop having a front section, a side section, and a rear section. The three sections are differently shaped allowing them to be used for different surgical purposes. By xe2x80x9claterallyxe2x80x9d is meant that the active electrode extend at right angles or at an acute angle, such as 45xc2x0, with respect to the longitudinal axis of the handpiece or the electrode shaft.
The constructions of the invention will provide the same important benefits not only for MIS of herniated disks but also for other MIS arthroscopic procedures where controlled electrode position and/or controlled heat generation is of importance as described in the prior applications, as well as for general electrosurgical procedures where the volumetric reduction of tissue or ablation of tissue is desirable.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention, like reference numerals designating the same or similar elements.